Backhoe actuator

ABSTRACT

A backhoe assembly is pivotally mounted to a prime mover by a Cshaped swing tower in a manner to reduce the moment arm between the prime mover support structure and the backhoe center of gravity. This is accomplished by nesting a hydraulic motor actuator and planetary gear reducer within the swing tower configuration for pivoting the backhoe assembly. In a preferred embodiment, the swing tower is pivotally mounted to a support which is slideable along a horizontal frame fixed to the prime mover. When the sliding support is positioned at either extremity of its sliding movement at one side of the prime mover, the backhoe may be swung toward the other side of the prime mover for transport and, because of the nesting arrangement, still be totally within the width defined by the frame.

United States Patent Shumaker 1 Dec. 30, 1975 1 BACKHOE ACTUATOR PrimaryExaminerLeo Friaglia Assistant ExaminerJohn P. Silverstrim 75 Inventor.ohn F d k Sh k M t I l f l er Dun Attorney, Agent, or FirmCullen,Settle, Sloman &

Cantor [73] Asstgnee: J. I. Case Company, Racine, Wis. [22] Filed: Apr.25, 1974 57 ABSTRACT [52] US. Cl. 214/138 R; 212/66 [51] Int. Cl. F161127/02; B66F 9/02 [58] Field of Search 214/138 R, 138 C; 212/66 [56]References Cited UNITED STATES PATENTS 2,978,116 4/1961 Wells et a1.214/138 RX 2,994,446 8/1961 Auwelaer et a1 212/66 X 3,243,053 3/1966Hanser et al 212/66 3,270,894 9/1966 Elliott et a1 212/66 3,376,9844/1968 Long et a1 214/138 R 3,698,580 10/1972 Carlson et al.... 214/138R 3,758,941 9/1973 Jackson et a1, 214/138 X 3,803,925 4/1974 Jackson214/138 R X 3,840,132 10/1974 Howells et a1. 214/138 R A backhoeassembly is pivotally mounted to a prime mover by a C-shaped swing towerin a manner to reduce the moment arm between the prime mover supportstructure and the backhoe center of gravity. This is accomplished bynesting a hydraulic motor actuator and planetary gear reducer within theswing tower configuration for pivoting the backhoe assembly. In apreferred embodiment, the swing tower is pivotally mounted to a supportwhich is slideable along a horizontal frame fixed to the prime mover.When the sliding support is positioned at either extremity of itssliding movement at one side of the prime mover, the backhoe may beswung toward the other side of the prime mover for transport and,because of the nesting arrangement, still be totally within the widthdefined by the frame.

10 Claims, 9 Drawing Figures US. Patent Dec.30, 1975 Sheet 1 Of63,929,239

US. Patent Dec.30, 1975 Sheet20f6 3,929,239

mm Dec.30, 1975 Sheet 3 of6 3,929,23

U.S. Patent Dec. 30, 1975 Sheet 5 of 6 3,929,239

US. Patent Dec. 30, 1975 Sheet 6 of6 BACIKHOE ACTUATOR BACKGROUND OF THEINVENTION l. Field of the Invention The present invention relates to abackhoe earth working implement mounted on a prime mover for pivotalmovement, and more particularly to the pivotal connection and powermeans for swinging the backhoe.

2. The Prior Art The backhoe, per se, is quite well known in the priorart, but many problems associated with its structure, and in particularwith its swing structure, have not yet been solved.

First, the very nature of the power means employed for swinging thebackhoe structure has been undesireable because of its inability togenerate sufficient torque for swinging the backhoe under heavy loadconditions. For example, prior art power means have included vane-typehydraulic motors and hydraulic cylinders which are driven by the powersource on the prime mover. However, the hydraulic structure formanipulating the backhoe boom and dipper is also interconnected to theprimary hydraulic pressure source on the prime mover. Therefore, when abackhoe bucket is being simultaneously lifted and swung, there is alimited amount of hydraulic pressure available for the backhoe swingingstructure. This can result in a jerky backhoe swinging motion which isan annoyance to the backhoe operator. In order to overcome this problemthrough the use of conventional power means, both the hydraulic pressuresource on the prime mover and the hydraulic power means for swinging thebackhoe must be enlarged. Such modifications are not only costly, butadd undesireable weight at the end of the prime mover to relocate theprime mover center of gravity and thereby interfere with its stabilityand operation during transport.

Prior art devices also are unable to provide a smooth, constant, andaccurate swinging motion for the backhoe assembly. These characteristicsare, again, due in part to the backhoe swinging power means beinginterconnected to the power source on the prime mover along with manyother hydraulic components. Having the ability to accurately control theswinging motion of the backhoe is very important because it is at timesabsolutely necessary that the backhoe bucket be posi tioned within asmall working area. For example, backhoes are commonly used for atrenching operation in an area where electrical lines, oil lines, or gaslines have previously been laid. In order to avoid these previouslyplaced lines, it is imperative that the backhoe operator be capable ofpositioning the backhoe bucket where desired.

Another shortcoming in the prior art is the inability to position thebackhoe assembly so that its center of gravity is near the prime moverfor transport yet have the backhoe assembly totally within the widthdefined by the opposed sides of the prime mover. Many prior art devicesare of the axial type wherein the supporting structure for the backhoeis stationary and centrally located behind the prime mover. Fortransport purposes, the backhoe assembly is generally collapsed to itsgreatest possible extent, i.e. the boom is raised to its highestinclination and the dipper is pivoted into close position with theraised boom, so that the center of gravity of the backhoe assembly isdrawn near the mounting end of the prime mover. In this situation, the

center of gravity of the backhoe assembly is usually still well behindthe end of the prime mover, so that during transport the prime moverexperiences a great deal of bouncing because of the over-hanging backhoeweight. Other prior art devices include a mounting frame for the backhoeassembly which is slideable transversely of the end of the prime mover.In these devices the mounting structure can be moved to one side of theprime mover, and the backhoe assembly is swung so that the boom projectstoward the other side of the prime mover. Positioningthe backhoe fortransport in such a manner does indeed move the backhoe center ofgravity closer to the prime mover; however, when the prior art devicesare positioned in this manner, the bucket and dipper extend well beyondthe side of the prime mover. This can be very undesirable when the primemover is driven on a highway, because the prime mover in effect becomesa wideJoad. Should this be the case, the prime mover then must be drivenpartly on and partly off the highway to thereby create an unpleasantdriving condition for the operator.

Another shortcoming in prior art backhoe assemblies arises from themounting arrangement between the those mounting arrangements generallyproduce an extended moment arm between the swing pivot axis and thebackhoe center of gravity. Quite naturally, this also results in agreater dimension between the backhoe center of gravity and the mountingend of the prime mover with the resultant problems discussed previously.Moreover, the extended dimension between the backhoe center of gravityand the pivot axis increases the moment loads established on the pivotmounting structure to thereby cause undue wear at these points. Theultimate result of this particular problem is increased cost andmaintenance that is occassioned by the necessity of having to replaceworn parts.

Prior art devices exhibiting the previously described problems include,first, U.S. Pat. No. 3,244,301 to Vaughan, which illustrates the use ofa hydraulic motor as the power source for the swinging backhoe. Theparticular arrangement disclosed by this patent results in several ofthe problems inherent in most of the prior art devices as previouslydiscussed. For example, in order for a hydraulic motor alone to generatethe sufficient port to swing the backhoe under heavy load conditions,the prime mover hydraulic power source and the hydraulic motor itselfmust be quite large in comparison to the power means proposed by thepresent invention. Further, as can be seen from the illustrations in theVaughan patent, the very nature of the mounting structure for thebackhoe assembly results in a relatively large moment arm measured forthe backhoe pivot axis and the backhoe center of gravity. As dis cussedpreviously, this creates wear problems on the pivot connecting elementsas well as locating the backhoe center of gravity further away from therear wheel supporting axis of the prime mover.

U.S. Pat. No. 3,270,894 to Elliott also discloses the use of a hydraulicmotor which can be removably positioned within the backhoe swing mastframe. The illustrations in this patent even more vividly point-out theproblems which were discussed in connection with the Vaughan patent,i.e. that the hydraulic motor for swinging the backhoe assembly must bequite large in comparison with the other backhoe components in. order togenerate sufficient torque to manipulate the swinging action of thebackhoe under all loading conditions and terrain conditions. As a resultof the necessity in having to utilize an enlarged driving member foreffecting thcswinging action of the backhoe, the other components of thebackhoe, for example, the boom, dipper and bucket, are positionedfurther away from the pivot axis and the prime mover. The Elliott patentalso fails to recognize the problem associated with backhoe transportposition and, quite naturally, therefore does not suggest the solutionfor positioning the backhoe center of gravity near the prime moverduring transport yet maintaining the backhoe within the lateral widithdefined by the opposed sides of the prime mover.

U.S. Pat. Nos. 2,994,446 and 3,174,635 to Van Auwelaer disclose yetanother power source for swinging a backhoe assembly, i.e. a vane-typehydraulic cylinder. ,This type hydraulic power source also has itsinherent problems, including the size problem as discussed previously inconnection with the Elliott and Vaughan patents. The size problem with avane-type hydraulic power source may even be more acute than withahydraulic rotary motor; the vane-type hydraulic power source reliesupon hydraulic pressure within the cylinder to act upon a single vaneface to generate the necessary power output for rotating the backhoe.Because of this structural limitation, the vane and the other componentsof the cylinder must be made as large as possible. As a result, theentire backhoe structure must be positioned further away from the pivotaxis and theprime mover, which results in the problems set forth above.

Another problem inherent and unique with the vanetype. cylinder powersource is hydraulic fluid leakage occasioned by misalignment between theshaft and barrel. components. Any such leakage results in the backhoeboom becoming displaced from its proper angular relationship withrespect to the power source, termed ,angular boom structure creep. Thisparticular characteristic can be quite annoying to a backhoe operatorbecause it requires him to apply a constant;

hydraulic pressure for a side cutting operation. Further,

structure will deflect under the loading conditions from the backhoeboom. This problem was recognized in U.S. Pat. No. 3,243,053 to Hanserand was attempted to be solved by the provision of an articulateconnection between the main frame and the upper and lower ends of theupright shaft. However, the l-lanser patent;

does not recognize the other problems associated with the use of avane-type cylinder and accordingly does not suggest the far superiormotive means suggested and proposed by the present invention.

Other prior art patents pertinent to the present inven tion include U.S.Pat. Nos. 3,155,250 to French and.

3,207,048 Rumsey. These patents, likewise, do not even suggesttheproblems nor the solutions which the presently proposed inventionsolves. Specifically, neither of these patents discloses a structuralarrangement which permits the use of a relatively small swinging powersource so that the center of gravity of the backhoe components may berelocated closer to the prime mover during both normal operation andtransport.

Even Pat. Nos. 3,376,984 and Re.26,439 to Long, which are assigned tothe assignee of the present application, do not exhibit the entire rangeof desireable features which are afforded by the present invention.

In short, the prior art fails in several material respects to suggest aswinging power source which is relatively small in construction butwhich can constantly generate the necessary torque for the entire rangeof backhoe operations. Further, the prior art does not suggest asolution to the problem of having the backhoe center of gravity locatedfar behind the prime mover, thereby resulting in instability for theprime mover during working operation and transport. These and otherproblems are overcome by the present invention.

SUMMARY OF THE INVENTION The present invention overcomes the prior artproblems previously discussed by employing and strategically locating ahydraulic motor actuator and planetary gear reducer to effect theswinging motion of the back- .hoe. This particular combination of powermeans, i.e.

the hydraulic motor actuator and the planetary gear reducer,synergistically provides versatility and smooth, accurate operation forthe backhoe. The hydraulic actuator is interconnected with the hydraulicpower source on the prime mover and requires much less hydraulic fluidfor driving purposes than does the prior art devices. The hydraulicmotor actuator has a torque to properly swing the backhoe under heavyload conditions and on sloping terrain.

The hydraulic motor actuator and planetary gear reducer are rigidlymounted to a frame attached to the rear of the prime mover such that theplanetary output shaft is free to pivot the backhoe swing tower andother backhoe components. The power which can be generated by thecombination hydraulic motor actuator and planetary gear reducer issufficiently great so that these two components can satisfy the maximumpower requirements of the backhoe yet be small enough to be nestedwithin the C-shape swing tower configuration. Because of this nestedarrangement, the entire backhoe assembly is located closer to the rearof the prime mover to reduce the cantilever moment arm between the primemover rear wheel axle and the backhoe center of gravity. As a result,the prime mover is more stable during both working operation of thebackhoe and transport. Further, the nesting arrangement enables theentire backhoe assembly to be located closer to the swinging pivot axisto reduce the moment arm on the pivot components. As a result, the pivotcomponents experience less wear to thereby add to the overalldesireability of the pivot arrangement proposed by the presentinvention.

In a preferred embodiment the support structure to which the hydraulicmotor actuator and planetary gear reducer are mounted in slideabletransversely across the end of the prime mover. This arrangement, perse, is known in the prior art to enable the backhoe to be positioned asdesired relative to the prime mover. However, the nesting arrangement inthe present invention enables the entire backhoe structure to be locatedcloser to the vertical pivot axis, as described previously. This overalltighter arrangement enables the backhoe to be positioned very near theend of the prime mover for transport yet be totally within the lateralwidth defined by the opposed sides of the prime mover. Specifically, thesliding frame member may be positioned at one side of the prime moverand the backhoe may be swung so that it projects toward the other sideof the prime mover without extending beyond that side of the primemover. Accordingly, the backhoe center of gravity is positioned closerto the prime mover end to reduce the cantilever moment arm from itscenter of gravity to the prime mover rear wheel axle. This results in amore balanced state for the prime mover during transport withouttransforming the prime mover into a wide load by having the backhoeproject beyond one side.

The entire realm of advantages afforded by the overall arrangementproposed by the present invention will be readily apparent from thefollowing discussion to those who are skilled in the art.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of the backhoefor the present invention mounted on the rear of a prime mover.

FIG. 2 is a perspective view illustrating the swing mounting structureand power means for the present invention.

FIG. 3 is an enlarged side view of the swing mounting structure andpower means.

FIG. 4 is a sectional view along line 44 in FIG. 3, illustrating thesplined connection between the backhoe swing tower and the power outputshaft.

FIG. 5 is a top plan view of the backhoe swing mounting structure andthe transverse sliding structure.

FIG. 6 is an enlarged view illustrating the sliding connection betweenthe backhoe and prime mover.

FIG. 7 is a vertical view of the sliding frame and stabilizing members.

FIG. 8 is a top plan view illustrating the backhoe transport position. 1

FIG. 9 is a vertical view illustrating the backhoe transport position.

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 illustrates a backhoe l0operably mounted to the rear of a prime mover 12, such as a tractor. Thebackhoe structure per se is well known in the art and includes thefollowing pivotally interconnected elements: a bucket 14, a dipper stick16, a boom 18 and a swing tower 20. The operation of the backhoe iscontrolled by an operator on the prime mover by a control console 22.The backhoe boom, dipper stick, and swing tower arrangement illustratedin FIG. 1 is substantially identical [0 that disclosed in U.S. Pat. No.3,376,984 to Long, which is incorporated by reference. That patentdiscloses the manner of pivoting the backhoe boom to an over-centerposition for transport to complement the structural arrangement proposedby the present invention. Theother components illustrated in FIG. 1, forexample the hydraulic cylinders for pivoting the boom, are conventionaland therefore will not be described in greater detail here.

As illustrated in FIGS. 2 and 3, the swing tower 20. has a C-shapedconfiguration opening toward the rear of theprime. mover and ispivotally mounted to an upper support plate 24 by bolt 26 andanti-friction components 28 and 30. The upper support plate 24 isrigidly mounted on a vertical supporting structure 32 which is rigidlymounted to a lower support plate 34. The support plates 24, 32 and 34comprise a sliding frame which can be positioned. at an infinite numberof transverse positions across the end of the prime mover. A pair ofplates 36 and 38 are rigidly connected to the forward side of thevertical support structure 32 to support the sliding frame. A pair ofstop blocks 40 and 42 are bolted to plates 36 and 38, respectively, tofit around guide rails 40 and 42, which are rigidly mounted to the primemover to provide a slide frame by conventional structure not forming apart of the present invention. As illustrated in FIGS. 5 and 6, theguide rails extend essentially entirely between the op- ,posed sides ofthe prime mover. FIG. 6 further illustrates the manner in which supportplates 38 and 42 are connected together to support the backhoe structureon the guide rail 46 of the slide frame.

A set of four hydraulic lock cylinders 48 and pistons 50 are provided inthe vertical support structure 32 to lock the slide frame at the desiredtransverse position across the end of the prime mover. The hydrauliccylinder and piston arrangement is substantially identical with thatdisclosed in U.S. Pat. No. Re.26,439 to Long, which is incorporated byreference. Hydraulic cylinders 48 are connected to the hydraulic powersource on the prime mover by a set of hydraulic lines (not shown). Tomaintain the backhoe structure as illustrated in FIG. 3, hydraulic fluidunder pressure is introduced into chambers 48 and 50 to maintain thepistons in abutting relationship against guide rails 44 and 46. When itis desired to move the backhoe structure transversely across the end ofthe prime mover, cylinders 48 are relieved of pressure by exhaustinghydraulic fluid from within through the hydraulic lines. To move thesliding frame relative to the prime mover, the backhoe is swung to oneside or the other and the bucket is placed against a rigid object or inthe ground. Then, the backhoe boom cylinder is actuated; since thedipper is held in position by the bucket the sliding frame assembly ismoved along the guide rails to a different position. When the operatorhas positioned the sliding frame assembly in the desired location,hydraulic cylinders 48 are once again pressurized to cause pistons 50 toabut against the guide rails and thereby lockin frame in place.

As illustrated best in FIG. 7, a pair of extendable stabilizer legs 52and 54 having stabilizer feet 56 and 58 are mounted at the opposed endsof the guide rails 44 and 46. As shown in FIG. 7, the stabilizer legshave been extended downwardly to ready the prime mover for the backhoedigging or trenching operation. When the backhoe is not in operation,for example during transport, the stabilizer legs 52 and 54 will beraised. Stabilizer feet 56 and 58 are pivotally connected to thestabilizer legs 52 and 54 in order to seat properly on sloping terrain.

The power means for effecting pivotal movement of the backhoe boomincludes a hydraulic motor 60 and a planetary gear actuator 62. Althoughnot illustrated, the hydraulic motor actuator 60 is mounted on theplanetary gear reducer 62 by a plurality of bolts. Likewise, theplanetary gear reducer 62 is mounted on lower support plate 34 by aseries'of radially arranged bolts. Hydraulic motor actuator 60 isconnected to the hydraulic power source on the prime mover by suitablehydraulic lines (not shown) through a cross-over relief valve or a checkvalve with an overload relief.

As illustrated in FIG. 3, an externally splined output shaft 64 from thehydraulic motor actuator 60 is fitted in mesh with an internally splinedinput shaft 66 within the planetary gear reducer 62. Output from theplanetary gear reducer is by way of an externally splined output shaft68, which extends through an opening 69 in lower support plate 34 tointerconnect to the swing tower by an internally splined fitting 70. Itcan be appreciated that much of the force transmitted to the swing tower20 from the backhoe assembly is transmitted to the externally splinedoutput shaft of the planetary gear reducer. In order for the outputshaft to withstand these forces it is formed of a harden, heat-treatedmetal. Further, bearings can be mounted between the lower support plate34 and the cylindrical portion of shaft 68 to withstand the backhoeloading forces.

In the preferred embodiment, the hydraulic motor 60 is comprised of acommercially available motor from T. R. W. Ross Gear Division. Thespecific motor proposed for utilization in the present invention isidentified as a M.A.B. 16 motor series having an externally splinedoutput shaft identified as 6-B (SAE 1499 Standard).

The particular planetary gear reducer proposed for use in the presentinvention is commercially available from either Borg Warner or FairfieldManufacturing Company, Incorporated. The unit manufactured by BorgWarner is identified as their Model 8 series and would requiremodifications to provide a power output shaft. The Fairfield unit isidentified as their 83A Model series; the particular unit designed forthe present invention is identified as S3Al2636, which number specifiesthe output shaft size, and the motor mount, coupling and reductionarrangements. Either of these particular units will provide a torqueoutput of 75,000 to 80,000 inch-pounds, which is sufficient to swing thebackhoe under all normal operating conditions, even when overloaded andworking on an incline. The proposed planetary gear reducer has a gearratio of 36 to 1, which is optimum for achieving the desired poweroutput when utilizing the hydraulic motor manufactured by Ross GearDivision.

The particular hydraulic motor and planetary gear specifications setforth in the two preceding paragraphs are, of course, merely exemplaryof the preferred mode contemplated by the inventor for carrying out thepresent invention. Other manufacturers also have available modelswhich'would be suitable for use in the overall invention of thisapplication.

The advantages afforded by utilizing a power means comprising acombination hydraulic motor actuator and planetary gear reducer arenumerous. First, the backhoe is capable of being swung a full 180 ormore without having to sacrifice power output. Second, the power outputfrom the power means can be varied according to the particular backhoeapplication and backhoe structure by utilizing a different gear ratio.In the prior art devices, such as the vane-type power cylinder, andhydraulic cylinders, the torque output was dependent upon the pressureof hydraulic fluid available from the power source on the prime moverand upon the size of the hydraulic power means. Since the availablehydraulic power from the prime mover was generally fixed, the torque forthe backhoe was governed by the size of the hydraulic cylinder, whichnecessarily required structural modifications depending upon the size ofthe hydraulic cylinder. As a further advantage, the combinationhydraulic motor actuator and planetary gear reducer proposed by thepresent invention provides a smooth, accurate operation for the backhoe,which is necessary for neat and precise digging and trenching. Thecombination hydraulic motor and planetary gear actuator also reduces theamount of play or sloppiness at the bucket while side-cutting a trench,because it does not drift of like the more common types of swingmechanisms (such as hydraulic cylinders or rotary hydraulic vanecylinders).

A further major advantage afforded by the combination hydraulic motoractuator and planetary gear reducer is that the combination isrelatively small in comparison to prior art power sources so that it canbe nested within the C-shaped swing power as illustrated in FIGS. 1-3.The nesting arrangement therefore enables the backhoe structure to belocated closer to the prime mover to reduce the cantilever forceproduced at the end of the prime mover by the weight of the backhoe. Asa result, the prime mover is much more stable both during backhoeoperation and transport. Additionally, the nesting arrangement enablesthe backhoe center of gravity to be located nearer the swing pivot axisto reduce the moment load forces on the pivotal connections between theswing power 20, the upper support plate 24 and the output shaft 68. Itcan be appreciated that any reduction in the distance between the pivotaxis and the backhoe center of gravity has a substantial effect on thereduction of the moment forces on the pivotal connections because theweight of the backhoe and the forces experienced during workingoperation are very substantial.

The nesting arrangement of the hydraulic motor actuator and planetarygear reducer within the C- shaped swing tower has yet another highlyadvantageous result. As illustrated in FIGS. 8 and 9, the backhoe boom,dipper and bucket may be positioned for transport such that thesecomponents are located totally within the lateral width defined by theslideable support frame. To place the backhoe components in the positionillustrated in FIGS. 8 and 9, the sliding frame assembly is positionedon the slide frame rails 44, 46 at one side of the prime mover in amanner as previously described. Next, the backhoe boom and dipperhydraulic cylinders are actuated to collapse the backhoe components tothe position illustrated in FIG. 1, wherein the boom and dipper sticklie on both sides of a vertical plane perpendicular to the tractorlongitudinal axis and through the swing tower pivot axis. Finally, theoutput shaft 68 from the actuator gear 62 is rotated until one of therubber bumper pads 72 or 74 abut against the sliding frame member 32 tolimit the pivoting action of the swing tower 20. It can be seen fromFIGS. 8 and 9 that when the backhoe components are in this position thebackhoe center of gravity is located very close to the rear of the primemover. Accordingly, the prime mover is much more stable duringtransport. As an example, the prime mover experiences much less bouncingaction during transport movement since the backhoe center of gravity ismuch closer to the rear wheel axle. Moreover, the entire backhoeassembly in this position is confined to a region between the opposedsides of the prime mover so that the prime mover can be driven onhighways without being considered a wide-load.

The present invention may be embodied in other specific forms withoutdeparting from the spirit or essential characteristics thereof. Thepresent embodiment is therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the following claims rather than by the foregoingdescription. All changes which come within the meaning and range ofequivalency of the claims are therefore intended to be included andembraced therein.

Having fully and completely described my invention, I now claim:

1. In a backhoe having a generally vertical support attachment, a swingtower having a pair of interconnected, vertically spaced supportmembers, one of said support members being pivotally connected to saidsupport attachment about a generally vertical pivot axis, a backhoe boomoperably mounted on said swing tower for earth working, the improvementof means for pivoting said swing tower relative to the supportattachment including a hydraulic motor actuator having an outputcomponent driving a planetary gear reducer said planetary gear reducerhaving a rotary power output shaft coaxial with said vertical swingtower pivot axis and nonrotatably connected to the other of said supportmembers, said hydraulic motor actuator and planetary gear reducer beingnonrotatably connected to said support attachment and being nestedbetween the vertically spaced swing tower support members so that themoment arm from the backhoe center of gravity to the support attachmentmay be reduced.

2. In a backhoe as defined in claim 1, wherein said swing tower isC-shaped in a vertical plane through the swing tower pivot axis, thefurther improvement of said hydraulic motor actuator and planetary gearreducer being nested within said C-shaped configuration.

3. In a backhoe as defined in claim 2, wherein said support attachmentis mounted to an end of a prime mover for slideable side-to-sidemovement along an axis generally perpendicular to the longitudinal axisof said prime mover, said backhoe further including a dipper pivotallymounted to said boom and an earth working implement, such as a bucket orthe like, operably mounted on said dipper, said backhoe boom and dipperbeing pivotable to a retracted transport position, the furtherimprovement of said planetary gear output shaft being rotatable 180 ormore to swing said backhoe boom and dipper within a range of positionsbetween 90 or more to either side of said prime mover longitudinal axis,said backhoe boom, dipper and earth working implement, in said transportposition, being totally within the width defined by the opposed sides ofsaid prime mover when said support attachment is at the extremity of itssliding movement toward one side of said prime mover and said boom anddipper are rotated 90 relative to said longitudinal axis toward theother side of said prime mover.

4. In an earth working implement, including a support structure having apair of horizontally oriented, vertically spaced support plates, a swingtower having a C-shaped configuration in a vertical plane, saidconfiguration defining a vertically oriented swing tower base and twohorizontally disposed legs, the upper leg of said 10 C-shaped swingtower being pivotally mounted to the uppermost of said support platesabout a vertical pivot axis, the other of said swing tower legs beingdisposed only beneath the lowermost support plate, a planetary gearreducer rigidly mounted to said lower support plate and a rotary powersource connected to and actuating said gear reducer, said rotary powersource and said gear reducer being nested within said C-shaped swingtower between said pair of support plates, said gear reducer having arotary output component driven by said rotary power source, said outputcomponent (a) being coaxial with said pivot axis, (b) extending beneathsaid lower support plate, and (c) being nonrotatably connected to theother of said swing tower legs for pivoting said swing tower.

5. In a backhoe including a support having a horizontally disposed loadbearing plate, a swing tower having a C-shaped configuration in avertical plane, an upper portion of said C-shaped swing tower beingpivotally mounted to said load bearing plate about a vertical pivotaxis, a backhoe boom, dipper and bucket operably mounted to said swingtower for earth working, said support being slidably mounted on alateral frame secured to a prime mover, the support being horizontally.

slideable along an axis perpendicular to the longitudinal axis of theprime mover, wherein the improvement comprises:

a rotary power member and gear reducer rigidly mounted to said supportand being nested with the C-shaped configuration of said swing tower;

said gear reducer having a rotary output shaft driven by said rotarypower member, said output shaft being coaxial with said vertical pivotaxis and being connected to said C-shaped swing tower for pivoting thebackhoe boom, dipper and bucket 180 relative to said rotary power memberand gear reducer; and

said output shaft being rotatable to swing the backhoe boom, dipper, andbucket to on either side of said prime mover longitudinal axis, saidbackhoe boom, dipper, and bucket being pivotable relatively to oneanother to a collapsed transport position, and being totally within thelateral width of the lateral frame when (1) said support is at eitherextremity of its limited horizontal movement, (2) said boom, dipper, andbucket are pivoted to their respective transport positions, and (3) saidboom, dipper and bucket are swung 90 relative to said longitudinal axistoward the other side of said prime mover.

6. In a combination tractor and backhoe having a guide frame mountedacross the back end of the tractor perpendicular to the tractorlongitudinal axis, a support slideable along the guide frame forpositioning the backhoe at different positions relative to the tractorlongitudinal axis, a C-shaped swing tower opening generally toward saidtractor and being pivotally mounted to said slideable support about avertical axis, said swing tower supporting the backhoe boom and dipperstick, the improvement of a rotary power means carried by the slideablesupport and being nested within the C-shaped swing tower for pivotingthe swing tower and backhoe about said vertical pivot axis, wherein saidrotary power means includes a rotary hydraulic motor actuator and a gearreducer, and said gear reducer having an output shaft non-rotatablyinterconnected with the swing tower, and said backhoe being positionedwithin the lateral width of the guide frame in a transport positiondefined by (a) said slideable support 11 i being at one side of thetractor at the extremity of its sliding movement along the guide frame,and (b) the swing tower, backhoe boom and dipper stick being pivotedtoward the other side of the tractor and being generally positionedperpendicular to the tractor longitudinal axis.

7. An earth working assembly operably mounted to one end of a primemover, said earth working assembly including a member having a firstload bearing surface, and earth working attachment having a pair ofvertically spaced, interconnected attachment members, one of saidattachment members being pivotally mounted to said first load bearingsurface about a generally vertical pivot axis, said pivot axisintersecting the other of said attachment members, a rotary powerhydraulic motor actuator drivingly interconnected with a planetary gearreducer, said power actuator and reducer being nested between thevertically spaced attachment members so that the moment arm between theearth working assembly center of gravity and the prime mover is reducedto correspondingly reduce stress on the pivotal connection between saidsupport and attachment, said reducer having an output shaft and saidhydraulic motor having an output component for driving the reduceroutput shaft through the planetary gear arrangement, wherein the torquerequirements for manipulating said earth working assembly may begenerated by a relatively compact power source and gear reducer nestedbetween the attachment members, said output shaft being coaxial withsaid pivot axis and being operably connected to the other of saidattachment members for pivoting said earth working attachment 12 withina range of 180 or more to a plurality of attitudes relative to saidprime mover.

8. The earth working assembly and prime mover defined in claim 7,characterized by said motor being hydraulically interconnected anddriven by a hydraulic power source on the prime mover.

9. The earth working assembly and prime mover defined in claim 7,characterized by said earth working attachment including a swing towerhaving a C-shaped configuration in a vertical plane through theattachment pivot axis, said hydraulic motor actuator and planetary gearreducer being nested within said C- shaped configuration.

10. The combination defined in claim 9, characterized by said earthworking assembly including a backhoe having a boom pivotally mounted tosaid swing tower, a dipper pivotally mounted to said dipper and a bucketpivotally mounted to said dipper, said backhoe components beingpivotable to a transport position, said support being slideably mountedon said prime mover along an axis perpendicular to the prime moverlongitudinal axis, said actuator output shaft being 180 to swing saidbackhoe components within a range of positions between to either side ofsaid prime mover longitudinal axis, said backhoe components, in saidtransport position, being totally within the width defined by theopposed sides of said prime mover when said support is at eitherextremity of its sliding movement toward one side of said prime moverand said backhoe components are pivoted 90 relative to said longitudinalaxis toward the other side of said prime mover.

1. In a backhoe having a generally vertical support attachment, a swingtower having a pair of interconnected, vertically spaced supportmembers, one of said support members being pivotally connected to saidsupport attachment about a generally vertical pivot axis, a backhoe boomoperably mounted on said swing tower for earth working, the improvementof means for pivoting said swing tower relative to the supportattachment including a hydraulic motor actuator having an outputcomponent driving a planetary gear reducer said planetary gear reducerhaving a rotary power output shaft coaxial with said vertical swingtower pivot axis and nonrotatably connected to the other of said supportmembers, said hydraulic motor actuator and planetary gear reducer beingnonrotatably connected to said support attachment and being nestedbetween the vertically spaced swing tower support members so that themoment arm from the backhoe center of gravity to the support attachmentmay be reduced.
 2. In a backhoe as defined in claim 1, wherein saidswing tower is C-shaped in a vertical plane through the swing towerpivot axis, the further improvement of said hydraulic motor actuator andplanetary gear reducer being nested within said C-shaped configuration.3. In a backhoe as defined in claim 2, wherein said support attachmentis mounted to an end of a prime mover for slideable side-to-sidemovement along an axis generally Perpendicular to the longitudinal axisof said prime mover, said backhoe further including a dipper pivotallymounted to said boom and an earth working implement, such as a bucket orthe like, operably mounted on said dipper, said backhoe boom and dipperbeing pivotable to a retracted transport position, the furtherimprovement of said planetary gear output shaft being rotatable 180* ormore to swing said backhoe boom and dipper within a range of positionsbetween 90* or more to either side of said prime mover longitudinalaxis, said backhoe boom, dipper and earth working implement, in saidtransport position, being totally within the width defined by theopposed sides of said prime mover when said support attachment is at theextremity of its sliding movement toward one side of said prime moverand said boom and dipper are rotated 90* relative to said longitudinalaxis toward the other side of said prime mover.
 4. In an earth workingimplement, including a support structure having a pair of horizontallyoriented, vertically spaced support plates, a swing tower having aC-shaped configuration in a vertical plane, said configuration defininga vertically oriented swing tower base and two horizontally disposedlegs, the upper leg of said C-shaped swing tower being pivotally mountedto the uppermost of said support plates about a vertical pivot axis, theother of said swing tower legs being disposed only beneath the lowermostsupport plate, a planetary gear reducer rigidly mounted to said lowersupport plate and a rotary power source connected to and actuating saidgear reducer, said rotary power source and said gear reducer beingnested within said C-shaped swing tower between said pair of supportplates, said gear reducer having a rotary output component driven bysaid rotary power source, said output component (a) being coaxial withsaid pivot axis, (b) extending beneath said lower support plate, and (c)being non-rotatably connected to the other of said swing tower legs forpivoting said swing tower.
 5. In a backhoe including a support having ahorizontally disposed load bearing plate, a swing tower having aC-shaped configuration in a vertical plane, an upper portion of saidC-shaped swing tower being pivotally mounted to said load bearing plateabout a vertical pivot axis, a backhoe boom, dipper and bucket operablymounted to said swing tower for earth working, said support beingslidably mounted on a lateral frame secured to a prime mover, thesupport being horizontally slideable along an axis perpendicular to thelongitudinal axis of the prime mover, wherein the improvement comprises:a rotary power member and gear reducer rigidly mounted to said supportand being nested with the C-shaped configuration of said swing tower;said gear reducer having a rotary output shaft driven by said rotarypower member, said output shaft being coaxial with said vertical pivotaxis and being connected to said C-shaped swing tower for pivoting thebackhoe boom, dipper and bucket 180* relative to said rotary powermember and gear reducer; and said output shaft being rotatable to swingthe backhoe boom, dipper, and bucket to 90* on either side of said primemover longitudinal axis, said backhoe boom, dipper, and bucket beingpivotable relatively to one another to a collapsed transport position,and being totally within the lateral width of the lateral frame when (1)said support is at either extremity of its limited horizontal movement,(2) said boom, dipper, and bucket are pivoted to their respectivetransport positions, and (3) said boom, dipper and bucket are swung 90*relative to said longitudinal axis toward the other side of said primemover.
 6. In a combination tractor and backhoe having a guide framemounted across the back end of the tractor perpendicular to the tractorlongitudinal axis, a support slideable along the guide frame forpositioning the backhoe at dIfferent positions relative to the tractorlongitudinal axis, a C-shaped swing tower opening generally toward saidtractor and being pivotally mounted to said slideable support about avertical axis, said swing tower supporting the backhoe boom and dipperstick, the improvement of a rotary power means carried by the slideablesupport and being nested within the C-shaped swing tower for pivotingthe swing tower and backhoe about said vertical pivot axis, wherein saidrotary power means includes a rotary hydraulic motor actuator and a gearreducer, and said gear reducer having an output shaft non-rotatablyinterconnected with the swing tower, and said backhoe being positionedwithin the lateral width of the guide frame in a transport positiondefined by (a) said slideable support being at one side of the tractorat the extremity of its sliding movement along the guide frame, and (b)the swing tower, backhoe boom and dipper stick being pivoted toward theother side of the tractor and being generally positioned perpendicularto the tractor longitudinal axis.
 7. An earth working assembly operablymounted to one end of a prime mover, said earth working assemblyincluding a member having a first load bearing surface, and earthworking attachment having a pair of vertically spaced, interconnectedattachment members, one of said attachment members being pivotallymounted to said first load bearing surface about a generally verticalpivot axis, said pivot axis intersecting the other of said attachmentmembers, a rotary power hydraulic motor actuator drivinglyinterconnected with a planetary gear reducer, said power actuator andreducer being nested between the vertically spaced attachment members sothat the moment arm between the earth working assembly center of gravityand the prime mover is reduced to correspondingly reduce stress on thepivotal connection between said support and attachment, said reducerhaving an output shaft and said hydraulic motor having an outputcomponent for driving the reducer output shaft through the planetarygear arrangement, wherein the torque requirements for manipulating saidearth working assembly may be generated by a relatively compact powersource and gear reducer nested between the attachment members, saidoutput shaft being coaxial with said pivot axis and being operablyconnected to the other of said attachment members for pivoting saidearth working attachment within a range of 180* or more to a pluralityof attitudes relative to said prime mover.
 8. The earth working assemblyand prime mover defined in claim 7, characterized by said motor beinghydraulically interconnected and driven by a hydraulic power source onthe prime mover.
 9. The earth working assembly and prime mover definedin claim 7, characterized by said earth working attachment including aswing tower having a C-shaped configuration in a vertical plane throughthe attachment pivot axis, said hydraulic motor actuator and planetarygear reducer being nested within said C-shaped configuration.
 10. Thecombination defined in claim 9, characterized by said earth workingassembly including a backhoe having a boom pivotally mounted to saidswing tower, a dipper pivotally mounted to said dipper and a bucketpivotally mounted to said dipper, said backhoe components beingpivotable to a transport position, said support being slideably mountedon said prime mover along an axis perpendicular to the prime moverlongitudinal axis, said actuator output shaft being 180* to swing saidbackhoe components within a range of positions between 90* to eitherside of said prime mover longitudinal axis, said backhoe components, insaid transport position, being totally within the width defined by theopposed sides of said prime mover when said support is at eitherextremity of its sliding movement toward one side of said prime moverand said backhoe components are pivoted 90* relative to saidlongitudinal axis toward the other side of said prime Mover.